From Wiki so another source could be helpful.
The NFL is giving the Chargers 100MIL towards a stadium if they stay in SD. But 200MIL if they move to LA? I'm not sure how accurate that is, but if it is true it's a bit strange IMO.
So the NFL gives/loans 200MIL to the Chargers which then gets handed over to the company Kroenke has created for the stadium and other development and then Spanos and some/all of the PSL's sold as well.
On January 14, 2016, the team filed paperwork for official trademark protection of the term "Los Angeles Chargers" for the purposes of running and marketing a professional football franchise.[12] Later in January, the Chargers submitted to the City of Santa Ana grading and landscape plans for a five-acre parcel of land in the city that could be used as the location of interim headquarters and training facilities "in the event the team exercises its option to relocate to the Los Angeles area."[81] After two weeks of negotiation, the Chargers and Rams came to an agreement in principle on sharing the planned City of Champions Stadium on January 29, 2016. The Chargers would contribute a $200 million stadium loan from the NFL and personal seat license fees to the construction costs and would pay $1 per year in rent to the Rams.[82]As an incentive to work out a stadium deal in their current market, the NFL pledged $100 million to the Chargers if they come to an agreement with the city of San Diego.[5] While the team had until March 2016 to decide if they would relocate to Los Angeles for the 2016 season, Chargers chairman/CEO Dean Spanos announced on January 29, 2016, that the team would remain in San Diego for the season. The announcement stated that the team would also be working over the year with government and business leaders on a new stadium proposal that could keep the team in San Diego long-term.[6] The Chargers had continued preliminary work on a ballot initiative for public approval on a new facility.[82] On February 23, 2016, the Chargers announced that their stadium efforts would be focused on a stadium in East Village, Downtown San Diego. On March 30, 2016, it was reported in the media that the details of the downtown stadium proposal were unveiled the stadium would be financed from $650 million from the team and the NFL, with a tax hike of $1.15 billion in bonds including $350 million city contribution, $600 million for the convention center, and $200 million to acquire land.